Flushing apparatus for vacuum pulp molding dies



1966 w. s. EASTMAN ETAL 3,228,826

FLUSHING' APPARATUS FOR VACUUM PULP MOLDING DIES Filed April 29, 1963 4 Sheets-Sheet 1- Wczl'son Sfczsfman Eugene Mfllsman INVENTORS Jan. 11, 1966 w. s. EASTMAN ETAL FLUSHING APPARATUS FOR VACUUM PULP MOLDING DIES 4 Sheets-Sheet 2 Filed April 29, 1963 Wai'son SiEasf'man Eugene .Mfllsmcm INVENTORS BY Zi 1966 w. s. EASTMAN ETAL 3,223,326

FLUSHING APPARATUS FOR VACUUM PULP MOLDING DIES Filed April 29, 1963 4 Sheets-Sheet 5 Watson SEasfman Eugene M.fi[1smcm IN V EN TORS 1966 w. s. EASTMAN ETAL 3,223,826

FLUSHING APPARATUS FOR VACUUM PULP MOLDING DIES Filed April 29, 1963 4 Sheets-Sheet 4.

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Wcrfson SEasiman Eugene Millsmarl L. up INVENTORS United States Patent 3,228,826 FLUSHING APPARATUS FUR VACUUM PULP MOLDING DllES Watson S. Eastman and Eugene M. Alsatian, Portland, Greg, assignors to Molded Container Corporation, a corporation of Oregon Filed Apr. 29, 1963, Ser. No. 276,616 7 Claims. (Cl. 162279) This invention relates to apparatus for cleaning vacu' um pulp molding dies by flushing them with a selected one or combination of fluid cleaning agents.

In the manufacture of molded pulp articles it has been conventional practice to dip vacuum forming dies into a pulp slurry, thereby forming on the die surface a pulp article having the contour of the die. The resulting article is consolidated and dehydrated, after which it is stripped from the die. The die then is recycled to the receptacle containing the pulp slurry for the formation of other molded articles.

Various prolbems have attended the forming apparatus employed in the foregoing procedure. Valving difficulties have interfered with the successful transfer of the pulp to the dies. The freshly molded articles are extremely fragile and diflicult to remove from the dies without breakage. The wet molded articles are diflicult to dry in the short drying cycle demanded of continuous commercial operations.

Cine of the most serious problems, however, is the tendency of the dies to become plugged. This difficulty is increased materially by the fact that the pulp slurries employed often are made from waste paper and magazine stock which may be loaded with fillers, pigments and adhesives. These materials build up deposits in various locations on the dies, with the result that imperfectly molded pulp articles are formed.

Because of their adhesive character, these deposits are quite difficult to remove. Also, the finely divided fibers which are the basic constituent of the slurries clog the small openings of the dies and lodge on various areas of the die surface.

Not infrequently a related difficulty is encountered in that, through defective operation of the transfer apparatus, an entire molded article may pass the transferring station without being removed from the forming dies. If it is not removed, it can cause serious damage to the forming machine because of the close tolerances which are present.

Accordingly it is the general object of the present invention to provide flushing apparatus which overcomes the foregoing disadvantages and which is broadly applicable to the cleaning of a wide variety of vacuum pulp molding dies.

It .is a particular object of the present invention to provide flushing apparatus for cleaning vacuum forming dies by the application of a selected one, or a selected combination, of various fluid cleaning agents.

Still another important object of the present invention is the provision of means for securing the general cleaning of .pulp molding dies without removing the dies from a continuously moving production line, while the dies are in inverted position and self draining, without diluting or polluting the pulp slurry in which the dies work.

The manner in which the foregoing and other objects of the invention are accomplished will be apparent from the accompanying specification and claims considered together with the drawings, wherein:

FIG. 1 is a view in side elevation of the herein described pulp molding apparatus;

FIG. 2 is an enlarged fragmentary view, partly in section, illustrating the die assemblies employed in the herein described pulp molding apparatus, their manner of mounting, and the manner in which they are passed through a pulp slurry;

FIGS. 3, 4 and 5 are transverse sectional views taken along lines 3-3, 44 and 55, respectively, of FIG. 2;

FIG. 6 is an enlarged fragmentary detail view illustrating still further the construction of the die and the manner of building up a pulp article on it;

FIG. 7 is a view in side elevation, partly in section, and partly broken away, of a vacuum roll assembly included in the herein described pulp molding apparatus;

FIG. 8 is a plan view partly in section of the vacuum roll of FIG. 7;

FIG. 9 is a transverse sectional view of the lower flight of the lower conveyor of FIG. 1 illustrating the application of the presently described flushing apparatus to the general cleaning of the dies after removal of the formed articles therefrom, but preliminary to the introduction of the dies into a further quantity of pulp for the formation of additional molded pulp articles; and

FIG. 10 is a detail plan view of one of the flushing units of the assembly of FIG. 9, looking in the direction of the arrows of line 1010 of FIG. 9.

Broadly considered, the presently described apparatus, used in conjunction with pulp molding apparatus including a conveyor mounting vacuum pulp molding dies, comprises flushing apparatus adapted and positioned to clean the dies after the molded articles have been removed rom them and preliminary to dipping them in the pulp slurry for the formation of additional molded articles.

The flushing apparatus includes a chamber communicating with the die behind the die face and a plurality of conduits communicating with the chamber. These conduits are connected to sources of various cleaning fluids such as air, water, steam, detergent, or chemical. Valve means are associated with the conduits for making the desired selection of cleaning agents.

Evacuating means are connected through valve means with one of the conduits, and pressured cleaning fluid dispensing means communicate with another of the condui ts through appropriate valving means.

Fluid jet means is positioned at a station in front of the die faces for spraying fluid thereon. It cooperates with the fluid cleaning agent supplied behind the die faces. In this way an efficient washing and flushing in both forward and reverse directions may be obtained, using any desired one or combination of fluid cleaning agents.

Considering the foregoing further and with particular reference to the drawings:

In carrying out the invention, vacuum forming dies are passed successively through a plurality of zones in which the various operations are carried out. As is apparent from FIG. 1, this is made possible through the employment of a pair of aligned partially overlapped endless conveyors indicated generally at 20, 22.

On lower conveyor 20 the vacum forming dies first pass through an article-forming zone A in which the dies, in inverted position, are dipped into a pulp slurry for forming the article on the die surfaces.

Next the dies, bearing the partly formed wet articles, are passed through a dehydrating and consolidating zone B where part of the water is removed from the articles by suction.

In the next zone, the drying zone C, hot gases are passed through the articles on the dies for drying the articles so that they may be handled safely, or for drying them completely if this is desired.

Next, in the pressing zone D, the dried articles are pressed against the dies in which they are contained for consolidating the articles and calendering their surfaces. This is accomplished by the application of pressing and transfer dies mounted on the overlapping endles conveyor 22.

In the transfer zone E which follows, the pressed articles are removed from the forming dies and transferred, for example, to an oifbearing conveyor.

Preliminary to being passed again through the article forming zone, the forming dies are passed through two cleaning stages. In the first, zone F, they are spot cleaned with steam, detergents, chemicals or other materials for the removal particularly of gummy deposits. In the second stage, carried out in zone G, the dies are subjected to a general washing designed to remove dirt and residual pulp.

The lower endless conveyor system 20, which carries the vacuum forming dies employed in the foregoing sequence, is supported between a drive roll assembly 24 and a vacuum roll assembly 26.

The drive roll assembly is mounted on a rotatable shaft 28 to which are affixed a pair of sprockets 30, an intermediate guide wheel not illustrated, and a drive sprocket 32.

The vacuum roll assembly is supported on a rotatable shaft 34 to which are afiixed a pair of sprockets 36 and an intermediate vacuum wheel 39, to be described in detail later.

Sprockets 3t), 36 mount a pair of drive chains 33 which by reason of their horizontal position provide upper and lower stretches between the two roller assemblies. The upper stretches of the chains are supported by horizontal tracks 40; the lower, by horizontal tracks 42.

The conveyor thus described supports a series of vacuum die assemblies arranged end to end in abutting relationship. The construction of these assemblies, and their manner of mounting on the conveyor, is evident particularly in FIGS. 2 and 3.

Each assembly is indicated generally at 50. It includes a die holder having a base 52, side walls 54 and a tapered bottom 56. The base is provided with a central vacuum aperture 58 and with a plurality of ribs 60.

The ribs support a die member 62 of appropriate construction and contour. Thus it may be fabricated from sintered metal, sintered glass, sintered plastic, or from perforated metal sheets overlaid with a screen.

In the special case illustrated in FIG. 6, the die member comprises a base 64 provided with numerous vacuum openings 66 and overlaid with a screen 63. The screen and base are maintained in position against the edges of walls 54 of the die holder by means of a retainer 70. When the die is immersed in a pulp slurry, and suction applied through opening 66, an article '72 of pulp builds up on the screen 68, in the contour of the die.

Although the die contour is widely variable, in the illustrated form of the invention, it assumes the shape of an egg carton having depressed areas '74 to receive the eggs and peaked areas 76 which act as dividers to separate the eggs- To support the die holders as they travel, first on the lower stretch, and then on the upper stretch of the endless conveyor, there are provided a plurality of rollers 78 on the margins of the base plate 52, on the side opposite chains 38.

Coupling means are associated with each die assembly to make possible coupling the die to a source of vacuum, in sealed relation, over a substantial duration of linear travel.

Thus in vacuum aperture '58 of the base of the die holder (FIG. 4), there is seated a resilient sealing ring. A pair of connecting pins 82, diametrically opposed, are pressed into the die holder bottom outside the sealing ring 80. A slide bar 84 having a vacuum aperture 86 receives the free ends of pins 82.

Resiliently compressive members such as springs 88, or lengths of rubber tubing, are mounted on pins 82, between die holder base 56 and slide plate 84.

Vacuum aperture 86 inthe slide plate and vacuum aperture 58 in the die holder base are in substantial registration and afford means of connecting the die holder to the source of vacuum.

The vacuum source is a vacuum pump of substantial capacity provided with a water trap. The pump com-- municates with a vacuum conduit system including main line 96 and branch lines 92, each of which is controlled by its own valve.

Branch lines 92 in turn communicate with a vacuum bar or vacuum trough 94 adjustably supported from slotted hanger bars 95. Vacuum trough 94 is formed with a central, downwardly facing channel 96 and with a guideway 98 which borders the channel. This guideway is dimensioned to receive slide bar 84 of the die assembly in sliding, sealed relationship.

Similar vacuum bars are associated with other units of the conveyor assembly. Thus an elongated vacuum bar 100 is associated with the upper stretch of the conveyor. It is connected to vacuum conduit 90 by means of valved branch lines 102. It works in the drying and pressing zones of the assembly, as will appear hereinafter.

A third vacuum bar 104 is connected through feeder line 106 .to vacuum conduit 90. It works in the washing zone G of the unit as also will appear hereinafter.

To bridge the gaps between the vacuum bars there are supplied rail segments 107 and 108 respectively which are traversed by slide plates 84 on the die holders during the intervals when the slide plates are not in the process of traversing one of the vacuum bars.

In this manner there is afforded a means for continuously applying vacuum to the dies as they progress linearly through the various zones. In article-forming zone A, vacuum is supplied through vacuum trough 94. In drying zone C, as well as in pressing zone E, it is supplied by vacuum trough 100. In washing zone G, it is supplied by vacuum trough 104.

In article forming zone A, the dies are passed in end abutting relationship through a vat 110 having a sloping bottom and arranged to extend beyond the end of vacuum roll 26. As the dies in their inverted position enter the upstream end of the vat and progress along the length of it, they are immersed progressively deeper in the slurry contained in the vat, suction being applied all the while. The pulp articles thereupon are built up on the dies to a depth determined by such factors as the consistency of the slurry, the intensity of the vacuum, the size of the openings in the dies, etc.

It is a particular feature of the invention, however, that exposing the inverted dies to the slurry over a relatively prolonged period of linear travel enables better control of the vacuum and of the deposition of the pulp on the dies, resulting in the formation of pulp articles of uniform wall thickness, which are softer and more resilient and have more uniform wall thicknesses than do the articles manufactured by prior art machines relying upon cylinder and die filling principles.

After leaving vat 110, the dies pass to zone B, the dehydrating and consolidating zone. Here three important operations are performed.

First, the forming of the articles against the die surface is completed. Second, the articles are dehydrated by the vacuum removal of a substantial proportion of wate, facilitating the subsequent drying operation and improving the strength of the articles. Third, the articles are held firmly against the die as they are transferred to the upper stretch of the conveyor, preventing injury to them.

These three functions are made possible by the inclusion in the assembly of a novel vacuum wheel 39, the construction of which is illustrated in FIGS. 7 and 8.

As mentioned before, this wheel is a component of vacuum roll assembly 26 which supports one end of the lower endless conveyor system. It is fixed to shaft 34 between sprockets 36. It includes a conduit 112, the

interiorof which is provided with a passageway 114 communicating with a vacuum line 116 through valve 118. The construction of the conduit is such that a semicircular extension 12% projects into the hollow hub 122 of the vacuum wheel.

Hub 122 communicates with a plurality of hollow spokes 12 These are spaced by angular distances corresponding to the distances between the vacuum apertures and the die assemblies.

The hollow spokes open out into a peripheral channel 25 along the rim of the wheel. This channel corresponds in function and lateral dimension to guideway 98 in vacuum trough 94. It is designed to receive slide bar 84 with the die aperture registering with the opening through the spoke.

Accordingly, as the die assembly is passed around wheel 39, vacuum is applied continuously to each die, sucking water from the molded pulp article on the die face, and dehydrating it while contemporaneously completing its formation and holding it securely in place. The die assemblies then are passed to Zone C in which the articles are dried.

In zone C the drying is eifectuated by passing hot gas through the articles and through the dies, still making use of the evacuating system. To this end the assemblies are passed along vacuum trough Tilt), with slide plates 84 sliding in the groove of the trough, in the manner described in conjunction with vacuum trough 94.

A burner 13f) heats a furnace 132, the resulting hot gases being passed by fan 134 into a hood-shaped oven 136 which is open at the bottom, with its side walls extending in close proximity to the side edges of the die holders. The die assemblies, which now have been rotated 180 from their inverted position in zone A, lie face up and accordingly the hot gases contained in the oven are sucked by the applied vacuum through the articles, through the dies and out through vacuum conduit 90.

By controlling the vacuum applied, the temperature of the gases, and the rate of travel through the heating zone, a very precise degree of drying of the pulp articles may be achieved. This may range, for example, from a rather cursory drying intended only to render the articles self-sustaining, to a drying so complete as to eliminate the necessity for a subsequent drying stage. The latter might be desirable in circumstances where a large article, not readily susceptible to rapid transfer and ordinary drying, is being manufactured.

The dried articles then are ready for the next stage of the operation which comprises pressing them and calendering their exposed surfaces in zone D. This procedure, in turn, is preliminary to removal of the articles from the dies and their transfer to an otfbearing conveyor in zone E.

Both of these functions are carried out through the agency of endless conveyor unit 22 which as mentioned above, overlaps and is aligned with endless conveyor 20.

The construction of endless conveyor 22 is known and hence it is not illustrated in great detail. However, it comprises a drive roll assembly Mil and an idler roll assembly 142 mounting an endless conveyor which includes chains 144i engaging sprockets 146, 148 on the respective rolls.

Mounted on the rolls are a plurality of male transfer dies These are complementary in contour to the female forming dies on the lower endless conveyor. They are mounted for actuation by a cam 152 between the raised, lowered and raised positions shown from left to right in FIG. 1.

As they traverse the lower stretch of conveyor 22, trans fer dies 15% communicate with a vacuum trough 154 which is similar in design and function to vacuum troughs 94, lt tl previously described. However, the length of the trough is discontinuous.

The length indicated at 156 is connected to a source of vacuum through conduit 1559. On the other hand, the

length indicated at 160 is connected through conduit 162 to a supply of air under pressure. In this manner the formed articles may be sucked up on the transfer dies in a first stage and, after a predetermined duration of linear travel, blown off the transfer dies onto an offbearing conveyor 164, suitably arranged to receive the articles.

Before this transfer is etfectuated, however, the articles are pressed and calendered in zone D by making use of the surfaces of the transfer dies as the press platens and calendering surfaces.

This is made possible by supplementing the action of cam 152 with lever means 166 pivoted to a cylinder 16S and so arranged as to bear down on the margins of each die holder as it passes the cylinder. A substantial but controlled pressure thus is applied to the transfer dies as required to consolidate the articles in the forming dies and to render their surfaces smooth and uniform.

After pressing the articles in zone D and transfering them in zone E, transfer dies moving counterclockwise into the transfer area on endless conveyor 22 are recycled to the pressing and calendering of further molded and dried articles.

The forming dies on conveyor 20, relieved of their burden of pulp articles and traveling clockwise, pass successively through cleaning zones F and G.

In zone F the areas of the dies which are fouled with deposits of gum, dirt or pulp, are cleaned selectively by the application of high pressure jet means employing high temperature steam, detergent, or chemical cleaning agent. This cleaning step is in the nature of a spot cleaning operation designed to loosen and remove stubborn deposits and to precede the general washing operation occurring in zone G.

The latter operation washes off any chemical applied by jet cleaner 18% in zone F. It also washes off dirt and loose fibers from the entire Working surface of the dies. In addition, it washes off any missed molded articles which, through faulty operation of the apparatus, were not removed from the dies in transfer zone B.

In order to accomplish these functions effectively, and to render the apparatus versatile in its application to the forming of various articles from diverse types of pulp slurries, it is essential that the dies be flushed with cleaning fluids of various selected categories, and in their forward or reverse directions as required to dislodge the particles from the small foramina of the die. These results are obtained by application of the apparatus illustrated in FIGS. 9 and l() of the drawings.

As the empty dies pass through zone G in inverted position, preliminary to being introduced into pulp vat 110, they traverse vacuum trough 1G4. In accordance with the present invention the elongated, open faced chamber 2'70 of this trough is employed to apply one or more selected cleaning fluids, either gaseous or liquid, to the inside face of the die.

Accordingly chamber 276 communicates with conduit 272 which, in turn, communicates with conduits 276, 278, 28f), 282, 284 controlled by valves 286, 283, 299, 292, 294, respectively. Each of these conduits connects to a cleaning fluid source, such as hot air, steam, detergent or hot water. One of the conduits, conduit 280, for example, may connect with a source of vacuum, through feeder line 166 (FIG. 1). Thus it is possible, by suitable adjustment of valves 2864M, to apply a selected one or selected combination of cleaning fluids to the interior of the die.

Cooperating with the flushing unit serving the inner face of the die is a second flushing unit which is applied to the outer surface of the die. This unit, which is indicated particularly in FIG. 10, is connected to a source of water or other cleaning liquid via conduit 2%. The latter conduit feeds a plurality of branch lines as required to flush the entire surface of the die eiliciently.

Accordingly the conduit is connected through branch lines 298, 3% with a pair of capped, parallel, longitudinally extending jet mountings 302, 304 equipped with a plurality of spaced jet nozzles 306. The nozzles are directed toward the face surface of the die with the object in view of spraying it with water at substantial velocity.

The angle of application of the jets from nozzles 396 is adjustable. This result is accomplished by connecting pipes 302, 304 to conduits 298, 300 by swivel means which in the simple, illustrated form of the invention, comprise threaded sections 308, 310. Levers 312, 314 connected to the underside of the pipes then provide a handy means for adjusting the pipes angularly as required to direct the sprays in the desired direction.

Supplementing the action of longitudinally extending jet assemblies 302, 304 is a transversely arranged spray connected to conduit 296 by conduit 316. This latter conduit is connected to transversely arranged spray pipes 318, 320 which are capped at their free ends.

The spray pipes are swiveled at a swivel connection to pipe 316 through threaded sections 322, 324. Their angular position is determined by adjustment of downwardly depending levers 326, 328.

Thus by manipulation of the presently described apparatus, various important effects can be achieved.

First, in normal operation, the lower flushing unit including longitudinally arranged jets 302, 364 and transversely arranged sprays 318, 320 may be operated c011- tinuously to wash fibers, dirt, chemicals and other foreign matter from the face surfaces of the dies. The materials removed in this manner may also include deposits loosened by the application of the selectively directed jets of unit 180 in zone F.

Since the dies are inverted, the flushing liquid runs down from them, making them self-cleaning. Also, since the dies are remote from pulp tank 110, the wash liquor can be collected separately and does not pollute and dilute the slurry in the slurry tank.

Where the nature of the deposit demands special treatment, this may be obtained by suitable adjustment of any one or several of valves 286-294. Thus, if it is desired to pass the cleaning liquid from the lower spray unit completely through the die for internal cleaning thereof, vacuum line 289 may be opened by adjusting valve 290. This evacuates trough 104 so that the cleaning liquid is sucked through the dies.

Similarly, if a reverse flushing is desired, air, steam, detergent, chemicals or hot water may be passed into chamber 270 by adjustment of one or more of the remaining valves. The fluids thus supplied then will cooperate with the liquid from the lower unit in cleaning the dies.

In this manner an efficient and thorough cleaning of the dies may be achieved while the dies remain in continuous, high level production. Thereafter the dies are ready for another pass through vat 110 in which another layer of pulp is applied to the die surfaces.

Both the upper and lower conveyor assemblies of the herein described apparatus may be driven synchronously from a common motor 230 through a suitable gear reducing unit 232. This motor drives a first chain 234, connected to sprocket 32 of drive roll 24 through a second chain 236 that drives at the same rate the drive sprocket of the drive roll unit 146 of the upper endless conveyor assembly.

OPERATION The operation of the herein described apparatus is as follows:

Vat 110 is filled with pulp slurry of the desired type and consistency. Die assemblies 50 are passed inverted into the pulp in zone A whereupon they take up a coating of the predetermined thickness forming the articles.

The dies leaving the vat pass zone B, wherein, by the continuous application of vacuum, the articles are dehydrated and consolidated. This is accomplished by passing the dies around a vacuum Wheel 39 having hollow spokes connected to a source of vacuum and communicating with the dies.

Next the dies are passed through zone C where they again are connected to the vacuum source which now serves the function of pulling hot gas from oven 136 through the articles and through the dies, thereby drying the articles to any predetermined degree without scorching them and without case hardening them as is the case when heated transfer dies are employed to serve the dr ing function.

Next, the dies are transferred to zone D where cylinders 168 apply pressure to transfer dies mounted on an endless conveyor 22. This further compresses the articles and calenders their surfaces, rendering them smooth.

In zone B release of suction applied to the forming dies on the lower conveyor assembly and concomitant application of vacuum to the transfer dies on the upper conveyor assemblies results in passing the articles from the former to the latter. They then are blown off on conveyor 164.

The forming dies on the lower conveying unit from which the articles have been removed now pass jet cleaning unit in zone F. This removes selectively gummy or hard deposits on the die which are diflicult to remove by general flushing. Thereafter the dies are passed to zone G where washing unit 200 subjects them to a general cleaning with water or selected cleaning fluids by direct washing or reverse flushing. This washes ofl loose fibers, dirt and any chemical which may have been applied in zone G so that the dies may be cycled to vat 110 for a deposit of a further quantity of pulp.

It is to be understood that the form of our invention herein shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of our invention or the scope of the subjoined claims.

Having thus described our invention, we claim:

1. In pulp molding apparatus including a conveyor mounting vacuum pulp molding dies, flushing apparatus operative to clean the dies, the flushing apparatus comprising:

(a) a chamber communicating with the dies behind the die faces as the dies are transported by the conveyor,

(b) a plurality of conduits communicating with the chamber,

(c) evacuating means communicating with one of the conduits,

(d) pressure cleaning fluid dispensing means communicating with another of the conduits,

(e) valve means in each of the conduits independently controlling the flow therein, and

(f) fluid jet means positioned at a station in front of the die faces for spraying cleaning fluid thereon as the dies pass the station.

2. The flushing apparatus of claim 1 wherein the chamber comprises an open faced trough and each die mounts an apertured slide plate adapted to seal off the trough as the die traverses it, the die communicating with the trough through the aperture in the plate, and sealing means sealing the aperture.

3. The flushing apparatus of claim 1 wherein the fluid jet means comprises a plurality of spaced spray heads arranged longitudinally and transversely of the die.

4. The flushing apparatus of claim 1 wherein the fluid jet means comprises a plurality of spaced spray heads arranged longitudinally and transversely of the die, the spray heads including means for angular adjustment.

5. The flushing apparatus of claim 1 wherein the fluid jet means comprises a plurality of conduits arranged longitudinally and transversely of the die, swivel means interconnecting the conduits with the source of fluid sup- (c) evacuating means communicating with the conduit,

(d) valve means on the evacuating means for controlling floW in said conduit, and

(e) fluid jet means positioned at a station in front of the chamber for spraying fluid onto the die faces as the dies are transported across the chamber.

References Cited by the Examiner UNITED STATES PATENTS 2,859,669 11/1958 Leitzel 162392 DONALL H. SYLVESTER, Primary Examiner. 

7. IN PULP MOLDING APPARATUS INCLUDING A CONVEYOR MOUNTING VACUUM PULP MOLDING DIES, FLUSHING APPARATUS OPERATIVE TO CLEAN THE DIES, THE FLUSHING APPARATUS COMPRISING: (A) A STATIONARY CHAMBER COMMUNICATING WITH THE DIES BEHIND THE DIE FACES AS THE DIES ARE TRANSPORTED BY THE CONVEYOR, (B) A VACUUM CONDUIT COMMUNICATING WITH THE CHAMBER, (C) EVACUATING MEANS COMMUNICATING WITH THE CONDUIT, (D) VALVE MEANS ON THE EVACUATING MEANS FOR CONTROLLING FLOW IN SAID CONDUIT, AND (E) FLUID JET MEANS POSITIONED AT A STATION IN FRONT OF THE CHAMBER FOR SPRAYING FLUID ONTO THE DIE FACES AS THE DIES ARE TRANSPORTED ACROSS THE CHAMBER. 